JP7240523B2 - Low-temperature burning hydrate fuel in gas generant formulations for automotive airbag applications - Google Patents

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. patent application Ser. incorporated into.

FIELD OF THE DISCLOSURE The present disclosure relates to gas generant compositions for inflatable restraint systems of motor vehicles having cold burning hydrate fuels comprising a thermally stable hydrate having a water release temperature of about 140° C. or higher.

This section provides background information related to the present disclosure that is not necessarily prior art.

Passive inflatable restraint systems have been used for over 25 years in various applications such as automobiles. Certain types of passive inflatable restraint systems, for example, use pyrotechnic gas generants to inflate airbag cushions (such as gas initiators and inflators) and actuate seat belt tensioners (such as micro gas generators). Minimize occupant injuries by Performance and safety requirements for automotive airbag inflators continue to increase in an effort to increase passenger safety while striving to improve functionality and reduce manufacturing costs.

A suitable gas generant provides a sufficiently high gas output at a high mass flow rate for the desired time interval to achieve the required work impulse of the inflator. One way to optimize gas generant performance and reduce system cost is to reduce the combustion flame temperature of the gas generant formulation. This seems counterintuitive as the gas temperature affects the amount of work the evolved gas can perform. However, high gas temperatures may be undesirable because combustion and associated thermal damage can result. Additionally, high gas temperatures can also lead to excessive reliance or sensitivity of the gas to heat transfer and overly rapid shrinkage profiles, which may be undesirable. To mitigate the effects of high combustion flame temperatures (e.g., for the purposes of this disclosure, high flame temperatures may be considered to be greater than 1700 K at combustion), a significant portion of the mass of the inflator is used in filtering systems. are often relegated to heat sinks in combination with It adversely affects the weight of the inflator and thus the efficiency of the system.

In certain aspects, the desired combustion flame temperature for gas generant formulations used in front-end applications is less than about 1900 K (1,627° C.), optimally from about 1400 K (1,127° C.) to about 1600 K (1,627° C.). , 327° C.). In addition to combustion flame temperature, two other important gas generant properties that help improve the efficiency of the inflator (and hence its size and weight) are the gas yield of the gas generant (moles/100 grams of formulation). ) and the ability of solid combustion products to remain in large lumps that are easily filtered from the gas stream (slag).

In new advanced inflator designs, it is desirable to reduce or minimize filter component and heat sink requirements as much as possible. As part of their new design, new low temperature combustion gas generant formulations are advantageous because they reduce heat sink requirements and improve performance. Gas generant flame temperatures below about 1700 K (1,427° C.) reduce filtering inflators that operate in a manner that provides adequate restraint and protection without risk of burns or injury to vehicle occupants in a crash. It has been shown to enable the device. Therefore, it is desirable to achieve high gas output at high mass flow rates and relatively low flame temperatures in gas generant formulations for automotive airbag applications.

This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all features.

Advantageously, the present disclosure in certain variations provides a gas generant composition for an automotive inflatable restraint system comprising a cold burning hydrate fuel. Cold-burning hydrate fuels contain carbon, hydrogen, oxygen, and transition metals. Cold-burning hydrate fuel is
(i) contains at least one functional group selected from the group consisting of amide, imide, hydroxyl, carboxylic acid, and combinations thereof;
(ii) has a molar ratio of oxygen to carbon of greater than or equal to about 0.5;
(iii) hydration of at least half of the water molecules;
(iv) a transition metal salt or transition metal complex of an organic compound having an exothermic heat of formation of at least about −400 kilojoules/mole;

In certain embodiments, the cold burning hydrate fuel further comprises nitrogen.

In certain aspects, the water release temperature of the cold-burning hydrate fuel is about 140° C. or greater as measured by differential scanning calorimetry (DSC) at a heating rate of 5° C./minute and a tolerance of ±0.1° C./minute. is.

In certain aspects, the cold burning hydrate fuel is selected from the group consisting of copper cyanurate dihydrate, copper melamine oxalate dihydrate, copper malonate hydrate, and combinations thereof.

In certain embodiments, the cold burning hydrate fuel is present at about 5% or more and about 50% or less by weight of the gas generant composition.

In a further particular embodiment, the gas generant further comprises a co-fuel present at greater than or equal to about 10% and less than or equal to about 50% by weight of the total gas generant composition. The gas generant also includes an oxidizing agent present at greater than or equal to about 25% and less than or equal to about 70% by weight of the total gas generant composition. The gas generant further comprises one or more gas generant additives present from 0% or more to about 15% or less by weight of the total gas generant composition.

In certain aspects, the cold-burning hydrate fuel is present at greater than or equal to about 5% and less than or equal to about 30% by weight of the gas generant composition.

In certain aspects, the gas generant composition has a maximum flame temperature (T _c ) during combustion of greater than or equal to about 1400 K (1,127° C.) and less than or equal to about 1700 K (1,427° C.).

In certain aspects, the gas generant composition comprises:
(i) a gas yield of the gas generant composition greater than or equal to about 5.7 moles/100 cm ³ ;
(ii) a linear burn rate of greater than or equal to about 18 mm per second at a pressure of about 10 megapascals (MPa); or (iii) a linear burn rate pressure index of less than or equal to about 0.35.

In certain embodiments, the gas generant composition comprises guanidine nitrate, 5,5'-bitetrazole diammonium (DABT), copper bisguanyl urea dinitrate, hexamine cobalt (III) nitrate, copper diammine bitetrazole, and combinations thereof. and a co-fuel selected from the group consisting of

In certain embodiments, the gas generant composition comprises a basic copper nitrate, an alkali metal or alkaline earth metal nitrate, an alkali metal perchlorate, an alkaline earth metal perchlorate, or an ammonium perchlorate, a metal Further comprising an oxidizing agent selected from the group consisting of oxides, and combinations thereof.

In certain embodiments, the gas generant composition comprises a co-fuel comprising guanidine nitrate present at greater than or equal to about 15% and less than or equal to about 50% by weight of the total gas generant composition and and an oxidizing agent comprising basic copper nitrate present in greater than or equal to about 70 weight percent and less than or equal to about 70 weight percent.

Advantageously, the present disclosure, in certain other variations, provides a low temperature hydrate selected from the group consisting of copper cyanurate dihydrate, copper melamine oxalate dihydrate, copper malonate hydrate, and combinations thereof. A low temperature combustion gas generant composition for an automotive inflatable restraint system containing combustion hydrate fuel is provided. The maximum flame temperature (T _c ) of the low temperature combustion gas generant composition upon combustion is about 1700 K (1,427° C.) or less.

In certain aspects, the cold-burning hydrate fuel is present at greater than or equal to about 5% and less than or equal to about 50% by weight of the cold-burning gas generant composition.

In certain embodiments, the low temperature combustion gas generant composition comprises a co-fuel present at greater than or equal to about 10% and less than or equal to about 50% by weight of the total gas generant composition. The low temperature combustion gas generant composition also includes an oxidizer present at greater than or equal to about 25% and less than or equal to about 70% by weight of the total gas generant composition. The low temperature combustion gas generant composition also includes one or more gas generant additives present from 0% or more to about 15% or less by weight of the total gas generant composition.

In certain aspects, the low temperature combustion gas generant composition comprises:
(i) a gas yield of the low temperature combustion gas generant composition of at least about 5.7 moles/100 cm ³ ;
(ii) a linear burn rate of greater than or equal to about 18 mm per second at a pressure of about 10 megapascals (MPa); or (iii) a linear burn rate pressure index of less than or equal to about 0.35.

In certain aspects, the low temperature combustion gas generant composition comprises guanidine nitrate, 5,5'-bitetrazole diammonium (DABT), copper bisguanyl urea dinitrate, hexamine cobalt (III) nitrate, copper diammine bitetrazole, and and a co-fuel selected from the group consisting of combinations of The low temperature combustion gas generant composition may also contain a basic copper nitrate, an alkali metal or alkaline earth metal nitrate, an alkali metal perchlorate, an alkaline earth metal perchlorate, or an ammonium perchlorate, a metal oxide , and combinations thereof.

Advantageously, the present disclosure in certain further variations provides copper cyanurate dihydrate, a co-fuel comprising guanidine nitrate, an oxidizing agent comprising basic copper nitrate, and one or more gas generant additives. wherein the maximum flame temperature (T _c ) during combustion is less than or equal to about 1700 K (1,427° C.).

In certain aspects, the copper cyanurate dihydrate is present at greater than or equal to about 5% and less than or equal to about 30% by weight of the low temperature gas generant composition. A co-fuel comprising guanidine nitrate is present at greater than or equal to about 15 weight percent and less than or equal to about 50 weight percent of the total low temperature combustion gas generant composition. The oxidizing agent, including basic copper nitrate, is present at greater than or equal to about 25 weight percent and less than or equal to about 70 weight percent of the total low temperature combustion gas generant composition. Additionally, the one or more gas generant additives are present at from 0% or more to about 15% or less by weight of the total low temperature burning gas generant composition.

In certain aspects, the low temperature combustion gas generant composition comprises:
(i) a gas yield of the low temperature combustion gas generant composition of at least about 5.7 moles/100 cm ³ ;
(ii) a linear burn rate of greater than or equal to about 18 mm per second at a pressure of about 10 megapascals (MPa); or (iii) a linear burn rate pressure index of less than or equal to about 0.35.

Further areas of applicability will become apparent from the description provided herein. The descriptions and specific examples in this summary are for illustrative purposes only and are not intended to limit the scope of the disclosure.

Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those skilled in the art. Numerous specific details are set forth, such as examples of specific compositions, components, devices, and methods, in order to thoroughly clarify the embodiments of the present disclosure. Those skilled in the art will appreciate that the use of specific details is not necessary and that the exemplary embodiments can be embodied in many different forms, neither of which should be construed as limiting the scope of the disclosure. do. In some exemplary embodiments, well-known processes, well-known device structures, and well-known techniques are not described in detail.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" may be intended to include plural forms as well, unless the context clearly indicates otherwise. The terms "comprise," "include," "comprise," and "have" are inclusive and thus exclude the presence of the recited functions, elements, compositions, steps, integers, operations, and/or components. The specification does not preclude the presence or addition of one or more other functions, integers, steps, operations, elements, components, and/or groups thereof. Although the open-ended term "comprising" is to be understood as an open-ended term used to describe and claim the various embodiments described herein, in certain aspects: This term may alternatively be understood as a more restrictive and restrictive term such as "consisting of" or "consisting essentially of". Accordingly, for any given embodiment that recites compositions, materials, components, elements, functions, integers, operations, and/or processing steps, this disclosure also includes such recited compositions, materials, Embodiments consisting of or consisting essentially of, components, elements, functions, integers, operations, and/or processing steps are also specifically included. When "consisting of," alternative embodiments exclude additional compositions, materials, components, elements, functions, integers, manipulations, and/or processing steps; when "consisting essentially of," , additional compositions, materials, components, elements, functions, integers, manipulations, and/or processing steps that substantially affect the basic and novel properties are excluded from such embodiments, Embodiments may include any composition, material, component, element, function, integer, operation, and/or process step that does not substantially affect the basic and novel properties.

The method steps, operations, and operations described herein should not be construed as requiring their performance in the particular order described or illustrated, unless specifically identified as that order of performance. . It is also understood that additional or alternative steps may be used unless otherwise stated.

When a component, element or layer is referred to as being “on”, “engaging”, “connected to”, or “coupled to” another element or layer, it refers directly to the other component, element or layer. Moreover, there may be intervening elements or layers that are engaged, connected or joined. In contrast, when an element is referred to as being “directly on,” “directly engaging,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers. Other words used to describe relationships between elements should be interpreted in a similar manner (eg, "between" and "directly between," "adjacent" and "directly adjacent," etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, third, etc. may be used herein to describe various steps, elements, components, regions, layers and/or sections, the steps, elements , components, regions, layers, and/or sections should not be limited by those terms unless stated otherwise. These terms may only be used to distinguish one step, element, component, region, layer or section from another step, element, component, region, layer or section. Terms such as “first,” “second,” and other numerical terms as used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first step, element, component, region, layer or section discussed below could be removed from a second step, element, component, region, layer or section without departing from the teachings of the exemplary embodiments. can be called

Spatial or temporal relative terms such as "anterior", "posterior", "medial", "lateral", "inferior", "lower", "lower", "upper", "upper" , may be used herein to describe the relationship of one element or function to another, for ease of explanation. Spatially or temporally relative terms can be intended to encompass different orientations of the device or system in use or operation in addition to the orientation shown in the figures.

Throughout this disclosure, numerical values represent approximate measures or limits for ranges that encompass the values given and embodiments for the stated values and minor deviations from embodiments having the precisely stated values. Except for the examples provided at the end of the detailed description, all numerical values (e.g., amounts or terms) of parameters herein, including the appended claims, are ``about'' the actual numerical value. It is to be understood that the term "about" modifies in all cases whether or not it appears before the . "About" indicates that the numerical values set forth allow for some imprecision (an approach to accuracy of the value, approximately or reasonably close to the value, approximately). Where the imprecision provided by "about" is not otherwise understood in the art in its ordinary sense, "about" as used herein means at least the and variations that may arise from the usual methods used. For example, "about" means 5% or less, optionally 4% or less, optionally 3% or less, optionally 2% or less, optionally 1% or less, optionally 0.5% or less, or certain Aspects can optionally include 0.1% or less.

Further, the disclosure of ranges includes disclosure of all values and subdivided ranges within the entire range, including the endpoints and subranges given in the range.

Exemplary embodiments will now be described more fully with reference to the accompanying drawings.

As used herein, the terms "composition" and "material" include at least preferred chemical constituents, elements, or compounds, but unless otherwise specified, additional elements, compounds, or used interchangeably to refer broadly to substances, which may also include substances.

The present disclosure contemplates compositions for gas generants that can be in the form of solid granules, pellets, tablets, and the like. Combustion of the gas generant produces inflation gas or effluent that is directed to an inflator (such as an airbag) within the inflatable restraint system. A variety of different gas generant compositions are used in vehicle occupant inflatable restraint systems. The choice of gas generant material depends on compliance with current industry performance specifications, guidelines and standards, safe gas or effluent generation, safe handling of the gas generant material, sustained stability of the material, and cost effectiveness in manufacturing. It depends on various factors such as effectiveness. The gas generant composition is preferably safe during handling, storage and disposal and is preferably free of azide.

In various aspects, the gas generant typically includes at least one fuel component and at least one oxidant component, which upon ignition burns rapidly to produce gaseous reaction products (e.g., _CO2 , _H2O , N ₂ ) may be included. One or more fuel compounds combust rapidly to form heat and gaseous products, for example, a gas generant combusts to produce heated inflation gas for an inflatable restraint system or to actuate a piston. . The gas generant composition also includes one or more oxidizing components, which react with the fuel component to produce gas products. "Slag" or "clinker" are other names for solid combustion products formed during combustion of gas generating materials. Ideally, the slag retains the original shape of the gas generant (eg, granules, pellets, tablets, etc.) and is large and easily filterable. This is particularly important when the inflator design includes a reduced mass filtering system for the purpose of reducing the size and weight of the inflator such as can be used with low temperature combustion gas generant formulations.

Advanced inflator design concepts incorporate reduced filter and heat sink mass. The use of low temperature combustion gas generant formulations reduces heat sink requirements. Additionally, it is desirable that the slag have very good low temperature combustion gas generants, as this reduces the mass of the filter. "Slugging" is defined as the term for certain solid combustion products produced during combustion of the gas generant, rather than passing through the filter and into the airbag, rather than passing through the filter and into the airbag, rather than being retained within the combustion chamber during combustion. means to form lumps. Slugging agents can be used to achieve that effect. Slugging agents are compounds or materials that are generally inert to combustion and melt at combustion temperatures to agglomerate or collect all solid combustion products. Examples of conventional slagging agents are silicon dioxide, aluminum oxide, glass, and other metal oxides that melt at or near combustion flame temperatures.

As noted above, one way to optimize gas generant performance and reduce system cost of gas generants for passive restraint systems is to reduce the combustion flame temperature of the gas generant formulation. In an efficient inflator design, the amount of screen pack used should be sufficient to filter the gas stream and cool it from combustion of the desired amount of gas generant to the desired temperature before entering the airbag. is. Desired combustion flame temperatures for gas generant formulations used in front end automotive inflator applications generally range from about 1400 K (1127° C.) or higher to 1900 K (1627° C.) or lower. As noted above, in addition to combustion flame temperature, two other important gas generant properties that help improve the efficiency of the inflator, and thus its size and weight, are the gas yield of the gas generant. and the ability of the solid combustion products to remain in large concretions that are easily filtered from the gas stream to form slag.

One conventional method for obtaining low temperature combustion gas generant formulations is to use a large particle endothermic coolant, such as aluminum hydroxide, which is referred to as "enhanced for copper-containing gas generants." in co-owned US Patent Application Publication No. 2014/0261927 entitled "Slag Formation", relevant portions of which are incorporated herein. Due to the large particle size of aluminum hydroxide, it can be used at high levels (eg, about 10-20%) without adversely affecting the burn rate of the overall gas generant formulation. Additionally, the decomposition of aluminum hydroxide releases water vapor, which participates in airbag inflation and helps maintain a high gas yield from the gas generant formulation. Their formulation removes slag very effectively. Although the use of aluminum hydroxide is an effective technique for cooling gas generants, the outstanding performance of the formulations is very sensitive to the particle size distribution of the aluminum hydroxide coolant, so batch-to-batch Particle size distribution must be tightly controlled to minimize variability.

The present disclosure provides alternative low temperature combustion gas generant compositions, particularly bases, that enable low flame temperatures (e.g., ≤ about 1700 K (1,427°C)) during combustion to be obtained while maintaining good performance. Compositions are provided that allow the use of specific co-fuel and oxidant combinations, such as copper nitrate and guanidine nitrate.

In various aspects, the present disclosure contemplates gas generant compositions for automotive restraint/airbag systems that include a low temperature burning hydrate fuel compound or composite. The cold-burning hydrate fuel is a transition metal salt of an organic compound or a transition metal complex salt of an organic compound. Cold-burning fuels include carbon, hydrogen, oxygen, transition metals, and may include nitrogen. Accordingly, the low temperature burning hydrate fuel may be a transition metal salt or transition metal complex of an organic compound. The transition metal can be any metal selected from Groups 3-12 of the IUPAC Periodic Table. Suitable examples of transition metals include copper (Cu), manganese (Mn), iron (Fe), cobalt (Co), and/or zinc (Zn).

As noted above, the organic portion of the compound includes the following elements carbon (C), hydrogen (H), and oxygen (O). In certain variations, the organic portion of the compound includes the following elements carbon (C), hydrogen (H), and oxygen (O).

The organic portion of the low temperature burning hydrate fuel comprises at least one functional group selected from the group consisting of amide, imide, hydroxyl, carboxylic acid, and combinations thereof. Suitable organic anions or organic complexes include cyanurates, melamine oxalates, and malonates, as further described below.

In certain aspects, the cold-burning hydrate fuel, and more specifically the organic portion of the cold-burning hydrate fuel, (iii) has an oxygen to carbon molar ratio of about 0.5 or greater.

In certain other aspects, the cold-burning hydrate fuel includes (iv) (stoichiometrically) hydration of at least half of the water molecules. Additionally, the cold-burning hydrate fuel has a water release temperature of about 140° C. or higher when heated at a uniform heating rate of 5° C./min with a differential scanning calorimeter (DSC) tolerance of ±0.1° C./min. have A 2 mg ± 0.1 mg powder sample can be used for the purposes of this test. A DSC instrument from TA instruments is suitable for this test. The water release temperature, in DSC, is the temperature at which water incorporated in the salt begins to disassociate from the salt when heated at a uniform heating rate. This can be tested when a stoichiometric amount of water is incorporated into the salt with sufficient attraction. In certain aspects, the cold-burning hydrate fuel compound has at least one molecule of hydration, and optionally two or more molecules of hydration, depending on the organic anion or salt. Water molecules chemically bound to transition metal salts or complexes can be observed by differential scanning calorimetry (DSC) when heated at a uniform heating rate of 5° C./min from at least 140° C. to 150° C. from the salt. It has sufficient bond strength not to dissociate. In the context of gas generant formulations, such hydrates can be considered to form thermally stable hydrated salts. In most hydrated salts, the chemical bonds that bind water molecules to the salt are very weak. Therefore, water dissociates from the molecule at about 100°C, which makes such hydrate compounds unsuitable for automotive applications, because the gas generant has accelerated heat generation at temperatures as high as 110°C. This is because it may be exposed to aging or undergo extreme use conditions, which may exceed 100°C, for example. However, in the low temperature burning hydrate fuel compounds provided by the present teachings, the binding is so strong that water does not disassociate from the salt until temperatures reach a minimum of about 140°C to about 150°C, thus allowing use as a gas generant in automotive systems. thermally stable to A considerable amount of energy is absorbed in the removal of water molecules. In addition, once removed, the water molecules contribute to the gas yield of the formulation, such that these fuel compounds provide unique low temperature burning, high gas yield fuels for automotive gas generant compositions. .

Thus, in certain variations, the A gas generant composition for an automotive inflatable restraint system is provided that includes a fuel compound having a thermally stable hydrate compound with a water release temperature of 0.100.

In another aspect, the cold-burning hydrate fuel (v) has a heat of formation of at least about −400 kilojoules/mole, where, by convention, the sign indicating an exothermic event/reaction is negative ( Thus, the more negative the value, the greater the heat of production of the exotherm). In certain variations, the cold-burning hydrate fuel (v) is at least this exotherm and has a more negative heat of formation, such as at least about -410 kilojoules/mol, optionally at least about -425 kilojoules/mol, Certain variations may optionally be more exothermic by having at least about −450 kilojoules/mole.

In various aspects, the low temperature burning hydrate fuel compounds of the present disclosure have each of the following characteristics. The low temperature burning hydrate fuel compounds are transition metal salts or transition metal complexes of organic compounds. The organic portion of the compound comprises carbon, hydrogen, oxygen, and optionally nitrogen, and at least one functional group selected from the list of amide, imine, hydroxyl, or carboxylic acid. The low temperature burning hydrate fuel compound has an oxygen to carbon molar ratio greater than 0.5 and a heat of formation of exotherm of at least -400 kilojoules/mole. In addition, those low temperature burning compounds have a minimum of half a water molecule chemically bound to the transition metal salt, and desirably enough so that the water molecules do not disassociate from the salt until at least about 140°C to 150°C. bond strength.

ケミカルアブストラクトサービス（ＣＡＳ）番号は６３５１６－７５－６であり、この化合物は、銅，ジアクアビス（１，３，５－トリアジン－２，４，６（１Ｈ，３Ｈ，５Ｈ－トリオナト－Ｎ１）－，（ＳＰ－４－１）－９ＣＩとも呼ばれる。この化合物には、２つ水分子の水和がある（シアヌル酸銅の各分子に結合する）。シアヌル酸銅二水和物は、１当量の水酸化第二銅と１当量のシアヌル酸との反応生成物であり、したがって熱的に安定な水和物であるシアヌル酸の水和銅ＩＩ塩を形成する。（水和の）水分子は約２００℃まで塩から解離しない。水分子の除去ではかなりの量のエネルギーが吸収され、一旦除去されると、水分子は、ガス発生剤配合物のガス収率、ひいては低温燃焼ハイドレート燃料の提供に役立つ。 In certain variations, the low temperature burning hydrate fuel compound comprises copper cyanurate dihydrate. Copper cyanurate dihydrate can be represented by the following structure:

The Chemical Abstracts Service (CAS) number is 63516-75-6, and this compound contains copper, diaquabis(1,3,5-triazine-2,4,6(1H,3H,5H-trionato-N1)-, Also called (SP-4-1)-9CI, this compound has two water molecules of hydration (attached to each molecule of copper cyanurate).Copper cyanurate dihydrate has one equivalent of It is the reaction product of cupric hydroxide with one equivalent of cyanuric acid, thus forming the hydrated copper II salt of cyanuric acid, which is a thermally stable hydrate. It does not disassociate from the salt up to 200° C. A significant amount of energy is absorbed in the removal of the water molecules, and once removed, the water molecules contribute to the gas yield of the gas generant formulation and thus the low temperature burning hydrate fuel. Helpful.

該化合物には、１つの水分子の水和がある（マロン酸銅水和物の各分子に結合する）。該化合物は、１当量の水酸化第二銅と１当量のマロン酸との反応によって形成される生成物であり得る。マロン酸銅水和物には、約２２５℃の水放出温度を有する熱的に安定な水の水和がある。 In certain variations, the low temperature burning hydrate fuel compound comprises melamine copper oxalate dihydrate complex. The _{stoichiometry} of melamine _copper oxalate dihydrate is as follows _: [3Cu( _C2O4 )]( _C3H6H6 ) ₂ . _2H2O . This compound has two water molecules hydrated (bonded to each molecule of melamine copper oxalate). The product can be formed by reaction of 3 equivalents of cupric hydroxide and 1 equivalent of 2:3 melamine oxalate. Melamine copper oxalate dihydrate has a thermally stable water hydration with a water release temperature of about 225°C.
In certain other variations, the low temperature burning hydrate fuel compound comprises copper malonate hydrate. Copper malonate hydrate can be represented by the following structure:

The compound has one water molecule hydration (bonded to each molecule of copper malonate hydrate). The compound may be the product formed by the reaction of one equivalent of cupric hydroxide and one equivalent of malonic acid. Copper malonate hydrate has a thermally stable water hydration with a water release temperature of about 225°C.

Accordingly, in certain aspects, the low temperature burning hydrate fuel compound of the present disclosure is selected from the group consisting of copper cyanurate dihydrate, copper melamine oxalate dihydrate, copper malonate hydrate, and combinations thereof. can be selected.

The present disclosure enables low flame temperatures during combustion and has a maximum combustion temperature of e.g. An alternative low temperature combustion gas generant composition is provided that can use certain fuel and oxidant combinations such as: In certain aspects, the maximum combustion temperature of the low temperature combustion gas generants provided by the present disclosure can be from about 1400 K (1,127° C.) or higher to about 1600 K (1,327° C.) or lower. Considering the fact that their low-temperature burning hydrate fuel compounds form thermally stable hydrates, their cooling properties are excellent and still provide good performance, including adequate gas yield, while nitric acid Larger amounts of co-fuels such as guanidine can be used in the gas generant formulation. As described further below, the low temperature burning hydrate fuel compound can participate in combustion (eg, as a fuel) and eliminate the need to use large particle size endothermic coolants. In addition, low temperature burning hydrate fuel compounds have high cooling capacity, thereby allowing a relatively small amount of compound to cool the formulation to the desired temperature, thereby maintaining high gas yields. Other cold-burning co-fuels appear to potentially meet those requirements for cold-burning gas generants, but many of their alternative options suffer from excessive pressure sensitivity of burn rate, low burn rate, and/or It does not provide formulations with desirable and outstanding properties, such as poor gas yield. However, according to the present disclosure, the low temperature burning hydrate fuel compounds of the present disclosure function as fuels capable of meeting all of those performance criteria to provide a low temperature combustion gas generant composition.

In certain aspects, the low temperature burning hydrate fuel compounds of the present disclosure are selected from the group consisting of copper cyanurate dihydrate, copper melamine oxalate dihydrate, copper malonate hydrate, and combinations thereof. obtain. The cold burning hydrate fuel comprises from about 5% or more to about 50% or less by weight of the gas generant composition, optionally from about 5% or more to about 45% or less by weight of the gas generant composition, optionally gas. about 5% or more and about 40% or less by weight of the generant composition, optionally about 5% or more and about 35% or less by weight of the gas generant composition, optionally about 5% by weight of the gas generant composition % to about 30% by weight, optionally from about 10% to about 30% by weight of the gas generant composition.

Although not limited to low temperature combustion gas generant compositions, in certain embodiments, the gas generant composition comprises a low temperature burning hydrate fuel compound that can be used as a co-fuel for low temperature combustion gas generant compositions at relatively low temperatures. . The gas generant composition may also include another primary fuel, one or more additional co-fuels, along with at least one oxidizer. Most fuels known in the art can be used in the art and generally impart certain desirable properties to gas generant formulations such as gas yield, burn rate, thermal stability, and low cost. is selected as Those fuels can be organic compounds containing two or more of the elements carbon (C), hydrogen (H), nitrogen (N), and oxygen (O). The fuel may also contain transition metal salts and transition metal nitrate complexes. In certain variations, preferred transition metals are copper and/or cobalt. According to certain aspects of the present teachings, co-fuels are selected for the gas generant compositions of the present invention whereby when combusted with certain copper-containing oxidants, such as basic copper nitrate, the resulting The maximum combustion flame temperature (Tc) obtained will be in the range of about 1400 K (1127° C.) or higher to 1700 K (1427° C.) or lower.

Examples of fuels useful in gas generants according to the present teachings include guanidine nitrate, 5,5′-bittrazole diammonium (DABT), copper bisguanyl urea dinitrate, hexamine cobalt (III) nitrate, copper diammine bitetrazole, and is selected from the group consisting of combinations of The fuels can be used alone or in combination with other co-fuels in addition to the cold burning hydrate fuel compounds to provide desired combustion characteristics. In addition to the cold-burning hydrate fuel compound, the cold-burning gas generant may include from about 10% or more to about 50% or less by weight of the total gas generant composition of such additional fuels. Suitable low temperature combustion gas generant compositions comprise from about 15% or more to about 80% or less, optionally from about 25% or more to about 70% or less, optionally by weight of the total amount of fuel components in the total gas generant composition. Optionally including a total amount of fuel that optionally comprises about 30% or more and about 55% or less of low temperature burning hydrate fuel compounds.

Specific oxidizing agents suitable for gas generant compositions of the present disclosure include, by way of non-limiting example, alkali metals (e.g., Group 1 of the IUPAC periodic table including Li, Na, K, Rb, and/or Cs). elements), alkaline earth metals (e.g., elements of group 2 of the IUPAC periodic table, including Be, Ng, Ca, Sr, and/or Ba), ammonium nitrates, nitrites, perchlorates, metal oxides ( Cu, Mo, Fe, Bi, La, etc.), basic metal nitrates (e.g. transition metal elements of the 4th period of the IUPAC periodic table, including Mn, Fe, Co, Cu, and/or Zn), ammonium nitrate (eg, elements selected from Groups 3-12 of the IUPAC Periodic Table), metal ammine nitrates, metal hydroxides, and combinations thereof. One or more co-fuel/oxidizers are selected with the fuel component to form a gas generant that effectively achieves high burn rates and gas yields from the fuel upon combustion. One specific non-limiting example of a suitable oxidizing agent includes basic copper nitrate. Gas generants may include combinations of oxidants such that the oxidants may be nominally considered primary oxidants, secondary oxidants, and the like.

The oxidizing agent comprises no more than about 70%, optionally no more than about 60%, optionally no more than about 50%, optionally no more than about 40%, optionally no more than about 30%, by weight of the gas generant composition. , optionally no more than about 25% by weight, optionally no more than about 20% by weight, and in certain embodiments, no more than about 15% by weight of the gas generant composition, respectively. obtain.

In certain variations of the disclosure, the gas generant composition comprises from about 25% or more to about 70% or less, and in certain variations, optionally from about 30% or more, by weight of the total gas generant composition. A total amount of oxidizing agent of up to about 60% by weight. When a secondary oxidant such as perchlorate is included in combination with a primary oxidant such as basic copper nitrate, about 1 part of the total gas generant composition is required to retain the low temperature burning properties of the gas generant. It can be limited to an amount greater than or equal to about 10% by weight.

The gas generant composition may optionally contain additional components known to those skilled in the art. Such additives typically function to improve the handling or other material properties of the slag remaining after combustion of the gas generating material and improve the ability to handle or process pyrotechnic materials. By way of non-limiting example, additional ingredients for the gas generant composition may be selected from the group consisting of flow aids, crush aids, metal oxides, and combinations thereof. When minor components or additives are included in the gas generant, they are no more than about 15% by weight of the total gas generant composition, optionally no more than about 10% by weight of the total gas generant composition, and In certain variations, it may optionally be present cumulatively at up to about 5% by weight of the total gas generant composition. By way of example, such additives may be selected from the group consisting of flow aids, crushing aids, slagging agents, coolants, metal oxides, and any combination thereof. When present in the gas generant composition, in certain variations, each additive comprises from 0% or more to about 5% or less, optionally from about 0.1% or more to about 5%, by weight of the gas generant composition. 4% by weight or less, and in certain variations can optionally be present from about 0.5% by weight or more to about 3% by weight or less, so that the total amount of additive is about 4% or less.

Non-limiting examples of press aids used during the compression process include lubricants and/or mold release agents such as graphite, calcium stearate, magnesium stearate, molybdenum disulfide, tungsten disulfide, graphitic boron nitride. may optionally be included in the gas generant composition. Conventional flow aids such as high surface area fumed silica can also be used.

Slag forming or slagging agents can be refractory compounds such as silicon dioxide and/or aluminum oxide. Examples of conventional slagging agents are aluminum, silicon, and titanium dioxide, refractory materials, or other metal oxides that melt at or near combustion flame temperatures. Coolants for reducing gas temperature include basic copper carbonate or other suitable carbonates.

The gas generant composition may optionally include metal oxides that function as viscosity modifying compounds or additional slag forming agents (in addition to the endothermic slag forming components described above). Suitable metal oxides may include silicon dioxide, cerium oxide, iron oxide, titanium oxide, zirconium oxide, bismuth oxide, molybdenum oxide, lanthanum oxide, and the like.

In certain aspects, the low temperature combustion gas generant has a maximum flame temperature (T _c ) during combustion of about 1900 K (1,627° C.) or less, optionally about 1700 K (1,427° C.) or less, and certain variations In an example, it can optionally be considered to be about 1600 K (1,327° C.) or less. In certain aspects, the low temperature combustion gas generants of the present disclosure have a relatively low maximum flame temperature (T _c ) during combustion, e.g. Hereafter, optionally from about 1400 K (1127° C.) or higher to about 1600 K (1327° C.) or lower in certain variations. Higher gas yields can thereby be achieved at those flame temperatures than are achieved with conventional compounds.

Such cold combustion gas generants enable reduced filtering inflator systems that operate in a manner that provides adequate restraint and protection without risk of burns or injury to vehicle occupants in a crash. It has been shown. Therefore, it is advantageous to minimize flame temperature. However, the cold burning hydrate fuel compound can be used in any gas generant and is not necessarily limited to cold burning gas generants.

According to certain aspects of the present teachings, a cold-burning hydrate fuel having a water release temperature of about 140° C. or higher and optionally a volumetric gas yield of about 5.7 moles/100 cm ³ of gas generant or higher. Improved gas generant compositions are provided that include the compounds. The product of gravimetric gas yield and density is the volumetric gas yield. In certain embodiments, the volumetric gas yield is about 5.8 moles/100 cm ³ of gas generant or greater, optionally about 5.9 moles/100 cm ³ of gas generant or greater, optionally about 6 moles/100 cm 3 of gas generant or greater. .0 mol/100 cm ³ or more, optionally about 6.1 mol/100 cm ³ or more of gas generant, optionally about 6.2 mol/100 cm ³ or more of gas generant in certain variations.

In certain variations, the gas generant is greater than about 2 g/cm ³ , optionally greater than or equal to about 2.1 g/cm ³ , and optionally greater than or equal to about 2.2 g/cm ³ in certain variations. has a mass density of

In addition to improved gas generant performance in terms of volumetric gas yield, relative rapidity as determined by the observed burn rate is also important in inflator gas generant design. Generally, the burn rate of a gas generant composition can be represented by a simplified equation:
r _b =k(P) ⁿ (equation 1)
where r _b is the burn rate (linear), k is a constant, P is pressure, n is the pressure exponent, the pressure exponent being the double logarithm of linear burn rate (r _b ) versus pressure (P) is the slope of the linear regression line drawn through the plot.

In various embodiments, gas generants provided by the present disclosure have desirably high burn rates that enable desirable pressure curves for airbag inflation. The linear burning rate "r _b " of a gas generating material can be expressed in length per hour at a given pressure. According to various aspects of the disclosure, the gas generant has a linear burn rate of about 18 mm per second or greater at a pressure of about 21 megapascals (MPa). In certain embodiments, the gas generant burn rate is about 19 mm per second or greater at a pressure of about 21 MPA, optionally about 20 mm or greater at a pressure of about 21 MPA, optionally about 21 mm per second or greater at a pressure of about 21 MPA; Optionally about 22 mm per second or more at a pressure of about 2 MPA, optionally about 23 mm per second or more at a pressure of about 21 MPA.

In certain aspects, gas generating materials with acceptable pressure sensitivity have a linear burn rate slope or pressure index (n) of about 0.35 or less, optionally about 0.3 or less. A material with a linear burn rate slope of about 0.35 or less can meet the high temperature to low temperature performance variation requirements and also reduce the performance variation and pressure requirements of the inflator. Therefore, in various aspects, it is desirable for the gas generating material to have a constant gradient over the pressure range of inflator operation, which typically ranges from about 1,000 psi (about 6.9 MPA) to about 5000 psi (about 34.0 psi). 5 MPA), desirably with a constant slope of about 0.35 or less.

As described further below, the low temperature burning hydrate fuel compound or complex can participate in combustion (eg, as a fuel) and eliminate the need to use large particle size endothermic coolants. Additionally, low temperature burning hydrate fuels have high cooling capacity, allowing relatively small amounts of compounds to cool the formulation to the desired temperature, thereby maintaining high gas yields.

In certain embodiments, the gas generant comprises a fuel in the form of a low temperature burning hydrate compound as described above, a secondary fuel (eg, co-fuel), and one or more oxidizers. The gas generant composition may include, in addition to the low temperature burning hydrate fuel compound, a basic metal nitrate oxidizing agent as described above, and a nitrogen-containing co-fuel such as guanidine nitrate. In certain variations, the low temperature combustion gas generant is selected from the group consisting of copper cyanurate dihydrate, copper melamine oxalate dihydrate, copper malonate hydrate, and combinations thereof. It includes a hydrate fuel compound, a co-fuel, and one or more oxidizers. The gas generant composition can be a low temperature combustion gas generant having a maximum flame temperature (T _c ) upon combustion of less than or equal to about 1700 K (1,427° C.). The gas generant has a linear burning velocity of about 18 mm per second or greater at a pressure of about 21 megapascals (MPa). Additionally, the gas generant has a gas yield of the gas generant composition of greater than or equal to about 5.7 moles/100 cm ³ .

The gas generant may comprise from about 5% or more to about 50% or less, by weight of the gas generant composition, of the cold-burning hydrate fuel compound, and from about 10% or more to about 50%, by weight of the total gas generant composition. a co-fuel present at less than or equal to about 25 weight percent to less than or equal to about 70 weight percent of the total gas generant composition; Further comprising one or more gas generant additives present. In certain variations, the cold-burning hydrate fuel may be present at greater than or equal to about 5% and less than or equal to about 30% by weight of the gas generant composition.

In another variation, the gas generant comprises from about 5% or more to about 50% or less, by weight of the gas generant composition, of a cold-burning hydrate fuel compound, and about 10% or more, by weight of the total gas generant composition. a guanidine nitrate co-fuel present at from about 50% by weight of the total gas generant composition; a basic copper nitrate oxidizer present at from about 25% by weight to about 70% by weight of the total gas generant composition; It may further comprise one or more gas generant additives present from 0% or more to about 15% or less by weight. In certain variations, the cold-burning hydrate fuel may be present at greater than or equal to about 5% and less than or equal to about 30% by weight of the gas generant composition. The low temperature burning hydrate fuel compound may be selected from the group consisting of copper cyanurate dihydrate, copper melamine oxalate dihydrate, copper malonate hydrate, and combinations thereof. Such gas generants can be low temperature burning and can have a maximum flame temperature (T _c ) during combustion of greater than or equal to about 1400 K (1,127° C.) and less than or equal to about 1700 K (1,427° C.).

In yet another variation, the gas generant comprises at least about 5% and no more than about 50% by weight of the gas generant composition, optionally at least about 5% and no more than about 30% by weight of the gas generant composition. a guanidine nitrate co-fuel present at from about 10% to about 30% by weight of the total gas generant composition, from about 25% by weight of the total gas generant composition to It may further comprise a basic copper nitrate oxidant present at about 70% or less by weight, and one or more gas generant additives present at from 0% or more to about 15% or less by weight of the total gas generant composition. In certain variations, the cold-burning hydrate fuel may be present at greater than or equal to about 5% and less than or equal to about 30% by weight of the gas generant composition. The low temperature burning hydrate fuel compound may be selected from the group consisting of copper cyanurate dihydrate, copper melamine oxalate dihydrate, copper malonate hydrate, and combinations thereof. Such gas generants can be low temperature burning and can have a maximum flame temperature (T _c ) during combustion of greater than or equal to about 1400 K (1,127° C.) and less than or equal to about 1700 K (1,427° C.).

In a further variation, the low temperature combustion gas generant composition comprises copper cyanurate dihydrate, a co-fuel comprising guanidine nitrate, an oxidizing agent comprising basic copper nitrate, and one or more gas generant additions. and wherein the maximum flame temperature (T _c ) during combustion is less than or equal to about 1700 K (1,427° C.). Copper cyanurate dihydrate is optionally present at from about 5% to about 30% by weight of the total gas generant composition, and the co-fuel comprising guanidine nitrate is present at about 15% by weight of the total gas generant composition. The oxidizing agent comprising basic copper nitrate may be present at from about 25% to about 70% by weight of the total gas generant composition, and one or more of the gas generant additive may be present from 0% or more to about 15% or less by weight of the total gas generant composition. Such low temperature combustion gas generant compositions have (i) a gas yield of gas generant of greater than or equal to about 5.7 moles/100 cm ³ , (ii) at a pressure of greater than or equal to about 10 megapascals (MPa) of greater than or equal to about 18 mm per second. and/or (iii) a linear burn rate pressure index of about 0.35 or less.

Various embodiments of the present technology can be further understood through the specific examples included herein. Certain non-limiting examples are provided to illustrate how to make and use the compositions, devices, and methods according to the present teachings.

Example 1

A gas generant comprising a cold burning hydrate fuel compound having a water release temperature of about 140° C. or greater is tested. More specifically, gas generant compositions designated Mixture 1 and Mixture 2 containing copper cyanurate dihydrate were tested to determine the effect of copper cyanurate dihydrate on flame temperature and basic copper nitrate. (bCN) and guanidine nitrate ( _GuNO3 ) as major components, with minor percentages of ammonium perchlorate co-oxidant and silicon dioxide ( _SiO2 ) as a slagging agent. Assess impact. The composition and experimental results are shown in Table 1.

Example 2

A gas generant comprising a cold burning hydrate fuel compound having a water release temperature of about 140° C. or greater is tested. More specifically, gas generant compositions called Mixture 3 and Mixture 4 containing melamine copper oxalate dihydrate were based on basic copper nitrate (bCN) and guanidine nitrate (GuNO ₃ ), A gas generant containing a small percentage of ammonium perchlorate co-oxidant and silicon dioxide (SiO ₂ ) as a slagging agent is tested for flame temperature and gas yield. Table 2 shows the composition and experimental results.

Example 3

A gas generant comprising a cold burning hydrate fuel compound having a water release temperature of about 140° C. or greater is tested. More specifically, gas generant compositions called Mixture 5 and Mixture 6 containing copper malonate hydrate were based on basic copper nitrate (bCN) and guanidine nitrate (GuNO ₃ ), and perchlorinated A gas generant comprising a small percentage of ammonium acid co-oxidant and silicon dioxide (SiO ₂ ) as a slagging agent is tested for flame temperature and gas yield. Table 3 shows the composition and experimental results. In particular, for example, with mixture 6, a low maximum flame temperature of about 1405 K can be achieved, although some reduction in volumetric gas yield may occur in such embodiments.

The foregoing description of embodiments is provided for purposes of illustration and description. It is not intended to be exhaustive or to limit disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable where applicable, even if not specifically shown or described. , can be used in selected embodiments. The same thing can be changed in many ways. Such variations are not to be considered a departure from the disclosure and all such modifications are intended to be included within the scope of the disclosure.

Claims (8)

A gas generant composition for an automotive inflatable restraint system comprising a cold burning hydrate fuel comprising carbon, hydrogen, oxygen and a transition metal, said cold burning hydrate fuel comprising:
(i) contains at least one functional group selected from the group consisting of amide, imide, hydroxyl, carboxylic acid, and combinations thereof;
(ii) has an oxygen to carbon molar ratio of 0.5 or greater ;
(iii) hydration of at least half of the water molecules;
(iv) a transition metal salt or transition metal complex of an organic compound having an exothermic heat of formation of at least −400 kilojoules /mole ;
wherein the cold-burning hydrate fuel is selected from the group consisting of copper cyanurate dihydrate, copper melamine oxalate dihydrate, copper malonate hydrate, and combinations thereof. generator composition. 2. The gas generant composition of claim 1, wherein said cold burning hydrate fuel further comprises nitrogen. The water release temperature of the low-temperature burning hydrate fuel is 140° C. or more when measured by differential scanning calorimetry (DSC) at a heating rate of 5° C./minute and a tolerance of ±0.1° C./minute. 3. The gas generant composition according to Item 1 or 2 . The cold-burning hydrate fuel is present in a range of 5% to 50% by weight of the gas generant composition, and the gas generant composition is optionally 10% by weight of the gas generant composition. to 50% by weight of the gas generant composition ; an oxidizer present in the range of 25% to 70% by weight of the gas generant composition; and 0% to 15% by weight of the gas generant composition. 4. The gas generant composition of claim 1 , 2 or 3 further comprising one or more gas generant additives present in the range of . The low-temperature burning hydrate fuel is present in a range of 5% to 30% by weight of the gas generant composition, and has a maximum flame temperature (T _c ) during combustion of 1400 K (1,127° C.) to 1700 K (1,127° C.). , 427° C.) . (i) a gas yield of the gas generant composition of 5.7 mol /100 cm ³ or more;
(ii) a linear burn rate of greater than or equal to about 18 mm per second at a pressure of 10 megapascals (MPa); or (iii) a linear burn rate pressure index of less than or equal to 0.35 . The gas generant composition according to any one of claims 1 to 3 . a co-fuel selected from the group consisting of guanidine nitrate, 5,5′-bitetrazole diammonium (DABT), copper bisguanyl urea dinitrate, hexamine cobalt(III) nitrate, copper diammine bitetrazole, and combinations thereof; and a base. selected from the group consisting of: copper nitrate, alkali metal or alkaline earth metal nitrate, alkali metal perchlorate, alkaline earth metal perchlorate, or ammonium perchlorate, metal oxides, and combinations thereof 7. The gas generant composition of any one of claims 1-6 , further comprising an oxidizing agent. a co- fuel comprising guanidine nitrate present in the range of 15% to 50% by weight of the gas generant composition and basic copper nitrate present in the range of 25% to 70% by weight of the gas generant composition; 8. The gas generant composition according to any one of claims 1 to 7 , further comprising an oxidizing agent comprising: